Unfortunately, the best time to buy a p & s of any type is really mid-Nov to mid-Dec, when the retailers are really fighting (at least in the US). I'd say splurge just a touch and make sure it's IS, just because it gets nicer shots . . . it gives them a real sense of pride, especially if you take an interest in the shots (have him send you some) and even print the occasional one out for them.
As others mentioned, what's your price range? If it's under $70 or so, watch for clearance deals, if it's at or under $100, just watch for a sale at Staples/Newegg etc. Used is perfectly fine, but "new" still feels more like a gift, especially if he can learn to "keep it nice".
Good luck; now that I read this thread, I just realized I've got to get my son back on the other side of the camera
He's better than my grandmother was with 110, but I'll blame the camera for that one.